JP7664932B2 - Air purification and sterilization unit - Google Patents

Description

[0001] Traditionally, high efficiency particulate air (HEPA) filtration systems have been used to treat environmental air and remove airborne particles. These systems utilize filters that are required to meet certain HEPA requirements, such as the ability to remove 99.97% of particles with diameters of 0.3 μm or greater from the air that passes through the filter. Although HEPA filtration systems are effective at removing airborne particles, they suffer from all the limitations common to filtration systems, such as filters becoming clogged over time and requiring constant monitoring and replacement. Additionally, filtration-based systems cannot inactivate chemicals, remove unwanted gases, or remove small molecules that cause odors. Furthermore, while HEPA filtration systems can remove some airborne contaminants, they cannot treat nearby surface contaminants.

[0002] Other systems may utilize activated carbon filters or electrostatic filters, which may be utilized to increase the ability to capture contaminants and improve the effectiveness of filtration, but still suffer from the aforementioned limitations common to filtration-based systems, such as filter replacement, degradation of filter performance over time, and an inability to treat surface contaminants.

[0003] Other air purification systems, commonly called "ionizers," are designed to emit negative ions into the surrounding air. These ions attach to positively charged pollutants such as pollen and dust, making them heavier and more likely to fall or be captured by collection plates. However, many of the pollutants are not destroyed or removed, but simply migrate to floors or walls, where they may re-enter the air after the negative ions have disappeared or dissociated. If collection plates are used, they must be cleaned and replaced periodically, just like any other filtration system.

[0004] Other air purification systems are designed to use ultraviolet (UV) radiation to inactivate and/or break down airborne contaminants. These systems are sometimes referred to as UV germicidal irradiation or UVGI air purifiers. The UV light is usually tuned to short wavelength UV light (UV-C light). In operation, air passes through the system and one or more UV lamps, which are intended to directly sterilize the air passing through with UV light. UVGI systems are capable of destroying some contaminants rather than capturing/filtering all of the contaminants that pass through, but they have limitations. Many contaminants, such as bacteria and mold, especially spores, cannot be effectively destroyed by short periods of UV light exposure. Also, some volatile organic compounds (VOCs) may be resistant to UV energy or, worse, may react with UV light, making them more harmful or exposing nearby individuals.

[0005] Photocatalytic oxidation (PCO) air purifiers are somewhat similar to UV air purification systems in that they utilize UV light. However, rather than using UV light to directly interact with passing pollutants, PCO systems shine the UV light onto a catalytic material. Water molecules in the ambient air react with the UV light and catalyst to produce various oxidants, such as hydroxyl radicals. The oxidants can attack organic molecular pollutants and break them down into less harmful substances.

[0006] Thus, rather than trapping contaminants, PCO systems are capable of destroying and removing contaminants from the treated environment. However, conventional PCO systems have some limitations. For example, the passing air must be close enough to the catalyst so that the generated oxidant can mix with the air and come into contact with airborne contaminants. Ideally, some of the generated oxidant should continue to pass beyond the catalyst and UV lamps so that it can reach nearby surfaces and treat surface contaminants as well.

[0007] Thus, several design decisions must be made regarding where to place the catalytic material and the UV assembly relative to each other and relative to the air flow path. Insufficient contact between the passing air and the catalytic material, or insufficient irradiation of the catalytic material, can result in reduced oxidant production, poor mixing of the oxidant with the air, or both, ultimately leading to suboptimal treatment of the contaminants. On the other hand, excessive contact between the catalyst and the air flow path and/or between the UV assembly and the air flow path can unnecessarily restrict airflow, which can increase the operating power demands required to run the system and/or reduce the volumetric airflow through the system. The reduced airflow can hinder the treatment effectiveness of the system, increase the time it takes to clean the target environment, and/or hinder the ability of the system to release oxidant far beyond the catalyst to treat surface contaminants.

[0008] Thus, there is a continuing need for improvements in PCO-based air purification systems. An effective air purification unit must be able to easily treat and purify the surrounding air.

[0009] Various objects, features, attributes, and advantages of the present invention will become apparent and will be more readily understood from the following description of embodiments considered in conjunction with the accompanying drawings and the appended claims, all of which form a part of this specification. In the drawings, like reference numerals may be utilized to designate corresponding or similar parts in the various views, and the various depicted elements are not necessarily drawn to scale.

[0010] FIG. 1 is a perspective view of an exemplary air purification device. [0011] FIG. 2 illustrates the air purification device of FIG. 1 with the access door in an open position to illustrate certain internal features of the device. [0012] FIG. 3 illustrates the air purification device of FIG. 2 with an interior panel removed to illustrate additional internal features of the device. [0013] FIG. 1 illustrates a PCO unit and fan assembly of an air purifier. [0014] FIG. 1 illustrates details of a PCO unit. [0015] FIG. 2 further illustrates a PCO unit with portions removed to better show certain internal features of the PCO unit.

Overview
[0016] An exemplary air purification device is described herein. In one embodiment, the air purification device includes a housing for housing a PCO unit and a fan assembly. The device may also optionally include a filter compartment for holding a filter, such as a HEPA filter. As described in more detail below, the air purification device is configured to provide effective purification and sanitation of air in a targeted indoor environment.

[0017] The air purification devices described herein are believed to be particularly beneficial for purifying and disinfecting air in healthcare environments such as hospital rooms, emergency rooms, operating rooms, doctor's offices, exam rooms, recovery rooms, nurseries, and the like. Thus, the air purification units described herein may beneficially reduce or prevent the occurrence of hospital acquired infections. The combination of HEPA filtration and PCO activity serves to remove contaminants (via filtration) and destroy/kill remaining contaminants/pathogens (via oxidizers generated by the PCO unit). Optionally, carbon filters and/or ionizers may also be added to further enhance the air purification effect.

[0018] The positional terms "up", "down", "right", "left", "front", "back", "forward", "rear", "vertical", "horizontal", "sideways", etc. are used for convenience in describing the relative positions of different components of the air purification device described herein. However, it will be appreciated that the operation of the components of device 100, including the PCO unit, is not necessarily orientation dependent, and thus in some applications the "down" side need not necessarily point in the direction of gravity, and the longitudinal axis of the PCO unit, for example, need not necessarily be perpendicular to the ground.

[0019] The embodiments described herein may also provide enhanced overall performance as compared to conventional systems or systems that do not have the same structural features and/or optimizations. As used herein, the term "enhanced overall performance" refers to the ability to better remove contaminants from a given room/environment on a power basis (e.g., per watt used by the device), volumetric basis (e.g., per ^cm3 captured by the device), or both, as compared to devices that do not have the same features and/or optimizations.

Air Purifier Overview
[0020] Figure 1 is an isometric view of an exemplary air purification device 100. The illustrated air purification device 100 includes a housing 102 in which other components, which will be described in more detail below, are housed. The housing 102 provides protection from the internal components of the device 100, such as moving parts (e.g., a fan) and emanating ultraviolet radiation (e.g., from an internal PCO unit).

[0021] The housing 102 may include one or more handles 104 so that the device 100 can be moved to a desired location. Such handles 104 may extend along the top side of the housing 102 as shown, and/or may be located along the side of the device 100 and/or in other suitable locations. The housing 102 may also include a set of wheels 110 (e.g., caster wheels) to make it easier to move and position the device 100 to a desired location.

[0022] The air purification device 100 may also include user controls 106, which may include indicator lights, fan speed controls, a timer, a power button, or combinations thereof. The outlet 108 allows air to flow outwardly to the surrounding environment after processing and purification within the device 100. An inlet 109 (see FIG. 2) may be located on the opposite side of the unit 100 to receive air from the surrounding environment. Thus, air flows through the device 100 in the direction indicated by arrow 112.

[0023] FIG. 2 illustrates the air purification device 100 in a partially open position. As shown, a portion of the housing 102 may be formed as a door panel 114 that can be selectively opened/closed by manipulating a door handle 116 to swing the door panel 114 open/closed. The door panel 114 may be opened to reveal a filter compartment 118 and an inner panel 122. The PCO unit 120 may extend partially through the inner panel 122 to allow access for service and/or replacement.

[0024] The filter compartment 118 is preferably sized and shaped to receive one or more air filters, such as HEPA filters. One or more other types of filters, such as carbon filters, may additionally or alternatively be used. A grille 119 may be positioned to separate the filter compartment 118 from the remaining interior compartment of the unit 100. Thus, when the air filter is positioned within the filter compartment 118, it is located between the inlet 109 and other internal components of the device, including the PCO unit 120 and the fan. The filter can be easily inspected and/or replaced by opening the door panel 114 without having to further open the device 100 or exposing the user to other components of the interior compartment.

[0025] Thus, the device 100 can be operated to combine the functionality of HEPA filtration with PCO activity to more effectively purify the air of a target environment. By using filtration prior to passing the air through the PCO unit, larger contaminant particles are filtered out, and those that cannot be filtered or that pass through the filter are then exposed to the oxidant generated by the PCO unit. This effectively results in a higher relative concentration of oxidant to contaminants, increasing the overall purification capacity of the device 100.

[0026] FIG. 3 illustrates the air purification device with the interior panel 122 removed to better visualize some of the components of the interior compartment 124. The device 100 may include one or more safety switches 126 (e.g., proximity sensors, mechanical sensors, etc.) that prevent operation of the internal components when the interior panel 122 is not in place. The one or more safety switches 126 may be configured to prevent operation of the fan assembly 130 and/or ultraviolet lamps of the PCO unit 120, for example.

[0027] The fan assembly 130 is coupled to the outlet 108 and configured to move air from the interior compartment 124 out through the outlet 108. The fan assembly 130 preferably includes a centrifugal type fan that receives air near the axis/shaft of the fan and moves it in a direction substantially perpendicular to the axis/shaft. In the illustrated embodiment, for example, air from below (and/or above) the fan assembly 130 enters along the axis of the fan and moves outward through the outlet 108.

[0028] In the illustrated embodiment, the fan axis is oriented vertically, although in other embodiments the axis may be positioned horizontally or at other suitable angles. The PCO unit 120 is not visible in the view of FIG. 3, but is preferably located generally upstream of the fan assembly 120, as will become apparent from the discussion associated with FIG. 4. One or more other types of fans, such as axial or crossflow fans, may additionally or alternatively be included.

[0029] FIG. 4 shows a bottom perspective view of the PCO unit 120 and fan assembly 130 with other components of the device removed to better view these components. Arrows 112 indicate the air flow path (although some air may enter the fan assembly 130 from above). As described in more detail below, the PCO unit 120 operates to generate oxidizers that are mixed with the air passing through. These oxidizers may then act to destroy contaminants present in the air passing through. At least some of the oxidizers may also pass outside of the device 100 to travel beyond the device 100 to the target environment. Such oxidizers may then contact surfaces within the target environment to provide a disinfecting action to such surfaces.

Photocatalytic oxidation unit
[0030] Figure 5 is a detailed view of the PCO unit 120. The PCO unit 120 is operably coupled to a ballast 128. The ballast 128 may include electronic circuitry for controlling the supply of power to the one or more ultraviolet lamps of the PCO unit 120. The PCO unit 120 includes a frame 142 configured to provide a structure for supporting and orienting the one or more ultraviolet lamps and one or more photocatalytic cell panels 140. The frame 142 may include a mounting 143 that connects to an access panel 144 that extends outside the interior compartment 124 to facilitate access to the PCO unit 120 (see Figure 2).

[0031] FIG. 6 is a diagram of the PCO unit 120 with one of the photocatalytic cell panels removed to better illustrate the internal components of the PCO unit 120. As shown, the PCO unit 120 preferably includes a plurality of ultraviolet lamps 150. The plurality of lamps 150 may be arranged in a vertical "stacked" fashion such that each lamp is disposed along a plane that is substantially parallel to the cell panel 140 and substantially parallel to the longitudinal axis 160 of the unit. Each ultraviolet lamp 150 may extend horizontally along a line that is transverse or substantially perpendicular to the air flow path (i.e., along the longitudinal axis of the unit 120). Although two lamps 150 are shown here, other embodiments may include more than two lamps 150, for example, three, four, five, or more such lamps 150.

[0032] The PCO unit 120 also includes an inner reflector 146 disposed between the first and second ultraviolet lamps 150 and extending in a direction substantially parallel to the longitudinal axis, similar to the lamps 150. The inner reflector 146 is configured to reflect light from each of the ultraviolet lamps 150 such that the reflected light has a greater likelihood of impinging on the photocatalytic surface of the cell panel 140. It has been surprisingly found that the use of the inner reflector 146 improves the overall photocatalytic activity of the unit 120, even though the inner reflector 146 is disposed between the lamps 150 and thus blocks a portion of the light from each lamp 150 from reaching a portion of the photocatalytic surface proximate the opposing lamp 150.

[0033] The inner reflector 146 also includes a base surface 145 and angled features 144 extending diagonally from the base surface 143. For example, as shown, the base surface 145 may be substantially parallel to the longitudinal axis, while the angled features 144 include one or more angled surfaces that may each extend transversely to the longitudinal axis. Providing such angled features 144 has been found to help diffuse and reflect the ultraviolet light in a manner that provides better interaction with the photocatalytic surface of the cell panel 140, thereby further increasing the overall photocatalytic activity of the device.

[0034] The angled feature 144 includes one or more tips 148 (i.e., the portion that extends furthest from the base surface 145). As shown, the tips may extend along a direction that is transverse (i.e., substantially perpendicular) to the longitudinal axis 160. Thus, the inner reflector 146 may be formed as a strip of metal or other suitable material that is formed/folded to create the angled feature 144. This configuration has been found to be functionally effective in enhancing the photocatalytic activity of the device while being easily manufacturable. The inner reflector 146 is also easily integrated into the frame 142 by inserting it into a side wall of the frame 142. An embodiment having more than one ultraviolet lamp 150 may include multiple inner reflectors (e.g., between each pair of lamps 150).

[0035] The PCO unit 120 may also include one or more outer reflectors 162. The outer reflectors 162 may be formed, for example, as part of the upper and/or lower frames 142. The outer reflectors 162 may extend inward toward the interior chamber of the PCO unit 120 and toward the ultraviolet lamps 150. Similar to the inner reflector 146, the outer reflector 162 provides an angled surface that serves to reflect ultraviolet light and thereby better direct the light to the photocatalytic surfaces of the cell panels 140. The outer reflector 162 may be formed by placing cuts 164 in the frame 142, which allows the outer reflector 162 to be easily formed by folding it into the desired angled shape.

[0036] In contrast to the inner reflector 146, the outer reflector 162 has a tip (i.e., an innermost portion) that extends in a direction substantially parallel to the longitudinal axis 160. It has been found that the combination of at least one outer reflector 162 having a tip running substantially longitudinally and an inner reflector 146 having one or more tips running transversely to the longitudinal axis 160 provides effective total reflection of UV light within the internal chamber of the PCO unit 120, thereby improving the photocatalytic activity and efficiency of the PCO unit 120.

[0037] From the perspective of the upper ultraviolet lamp 150, for example, the nearby outer reflector 162 on the upper side of the frame 142 includes angled surfaces that help reflect and direct light in the "forward" and "backward" directions, as well as "up" and "down", and the inner reflector 146 includes angled surfaces that help reflect and direct light in the "left" and "right" longitudinal directions, as well as "up" and "down". The combination of reflective surfaces provides an overall configuration that effectively helps direct light onto the photocatalytic surface for effective photocatalytic activity.

[0038] During operation, the lamps 150 are energized and emit ultraviolet light toward the catalytic surfaces of the cell panels 140, thereby generating an oxidizer. The oxidizer then mixes with the passing air to provide sanitation of the passing air. Preferably, at least a portion of the oxidizer passes out of and beyond the device 100 with the passing air.

[0039] The cell panel 140 includes a photocatalytic coating. The photocatalytic coating is disposed on at least the inner surface of the cell panel 140 facing the ultraviolet lamp 150. Preferably, the photocatalytic coating also extends to the opening of the cell panel 140 to coat the surface of the opening. The photocatalytic coating may include a metal oxide, such as titanium oxide, and may optionally include one or more transition metals and/or alloys of transition metals. Examples of additional or alternative photocatalytic materials that may be utilized in the coating include graphene oxide, metal-organic frameworks (MOFs), other semiconductor materials, quantum dots, tantalite, other oxides (e.g., zinc, copper, iron, cadmium, tin, zirconium, or gallium oxide), sulfides (e.g., zinc sulfide), silica, and combinations thereof.

[0040] Oxidants generated during operation of the device may include, for example, hydrogen peroxide, hydroxide, free oxygen molecules, superoxide ions, and ozone. Preferably, however, the PCO unit 120 is configured to limit or eliminate the generation of ozone. Although ozone is a powerful oxidant, excess ozone can cause respiratory irritation in sensitive individuals. It has been found that by tuning the PCO unit 120 to produce effective levels of oxidants while minimizing or eliminating ozone, effective purification performance is maintained without the potential harmful effects associated with excess ozone.

[0041] To provide these performance characteristics, the ultraviolet lamp 150 preferably emits light having a wavelength of about 185-254 nm. The lamp 150 is typically rated at about 3-20 watts, more preferably about 5-10 watts. It has been found that using a lamp 150 having a rating within the aforementioned range can effectively balance the need to provide sufficient energy to achieve the required photocatalytic activity without creating excessive power inefficiencies and/or taking up too much space.

[0042] The structural configuration of the PCO unit 120 is designed to provide effective photocatalytic activity, effective interaction between the airflow and the generated oxidant, and effective overall volumetric airflow within the size constraints of the air purification device 100. These functions interact with each other, and enhancing one of these functions may involve a tradeoff with one or more of the other functions.

[0043] For example, photocatalytic activity can be enhanced by increasing the overall surface area of the ultraviolet lamps (e.g., using larger lamps) and/or by increasing the proportion of photocatalytic material in the air flow path. However, either of these modifications would likely increase the airflow resistance of the device and thus reduce the volumetric airflow or require more power to maintain a higher pressure throughout the device. Furthermore, the size of the airflow path cannot simply be increased indefinitely, since it is dictated by the overall size of the air purification device 100, which should preferably be kept within reasonable limits. However, restricting the air flow through the PCO unit 120 would mean a lower air turnover rate for the target environment, which would mean longer and/or less effective air purification.

[0044] Similarly, airflow can be increased by limiting the contact of the air with the photocatalytic material, such as by simply passing the air over the photocatalyst rather than through multiple openings, or by increasing the size of the openings. However, this limits the interaction of the air with the generated oxidant, and limits the mixing and distribution of the oxidant within the air. Thus, for a given level of generated oxidant, the oxidant is less likely to come into contact with and process contaminants. Similarly, airflow can be increased by increasing the spacing between the ultraviolet lamp 150 and the cell panel 140 and/or by decreasing the overall surface area of the ultraviolet lamp 150, but this tends to reduce the overall photocatalytic generation of oxidant.

[0045] Smaller openings tend to restrict air flow to a greater extent than larger openings. However, smaller openings tend to provide greater photocatalytic activity because the coated interior surface of the opening may provide a significant portion of the photocatalytic activity of the device and because smaller openings provide a greater overall area of active photocatalytic surface.

[0046] Setting the average cross-sectional area of each opening greater than about 0.1 ^mm2 and less than about 10 ^mm2 has been found to provide effective photocatalytic activity without unduly restricting airflow. More preferably, the openings have an average cross-sectional area of about 0.2 ^mm2 to about 5 ^mm2 , or about 0.3 ^mm2 to about 1 ^mm2 . Openings that are too small tend to reduce the overall performance of the device by unduly restricting airflow, and openings that are too large tend to reduce the overall performance of the device by unduly restricting photocatalytic activity.

[0047] The number of openings included in the cell panel 140 may vary. Preferably, the openings are provided in a number such that about 25% to about 75% of the planar surface area of the cell panel 140 is made up of openings, and more preferably, about 35% to about 65%, or about 40% to about 60% of the planar surface area of the cell panel 140 is made up of openings. Note that the "planar surface area" refers to the two-dimensional surface area of the upper surface of the cell panel 140 when laid flat and viewed from above.

[0048] The width of the cell panels 140 can also be varied. Wider cell panels provide longer openings with a larger overall surface area and therefore greater photocatalytic activity, but also increase the length that air must pass through the openings, thus increasing airflow resistance.

[0049] "Cell fraction" is defined herein as the combined width of the cell panels 140 divided by the overall width between the cell panels 140 (from outer surface to outer surface). The PCO unit 120 may be configured with a cell fraction of about 0.2 to about 0.7, more preferably about 0.3 to about 0.6, and even more preferably about 0.4 to about 0.5. Setting the cell fraction within the aforementioned ranges has been found to provide improved overall performance of the PCO unit 120.

[0050] The distance between the lamp 150 and the inner surface of the cell panel 140 can also be varied by adjusting the diameter of the lamp 150 and/or by adjusting the distance between the cell panels 140. Increasing the distance between the lamp 150 and the cell panel 140 can increase the residence time of the air passing through the PCO unit 120, but increasing the distance between the lamp 150 and the cell panel 140 reduces photocatalytic activity.

[0051] "Light fraction" is defined herein as the width/diameter of one of the lamps 150 divided by the overall distance between the inner surfaces of the opposing cell panels 140. The PCO unit 120 may be configured with a light fraction of about 0.45 to about 0.7, more preferably about 0.5 to about 0.6. Configuring the PCO unit 120 so that the light fraction is within the aforementioned ranges has been found to provide improved overall performance.

[0052] The following description provides some additional dimensions of an exemplary PCO unit 120 that have been found to provide effective performance in some applications, particularly those involving a modular, mobile, room cleaning device as described herein. However, it will be understood that the exemplary dimensions are not necessarily limiting and other embodiments may be sized or scaled to provide the needs of a particular application.

[0053] In one embodiment, the PCO unit 120 may have an overall height of about 2-4.5 inches (about 5.1 cm-114 cm), an overall width of about 1.5-2.5 inches (about 3.8-6.4 cm), and an overall length of about 4-8 inches (about 10-20 cm). The cell panel 140 may be of any suitable size and may have a width of about 5 mm to about 30 mm, more preferably about 10 mm to about 20 mm, and even more preferably about 10 mm to about 15 mm. The ultraviolet lamp 150 may also be sized appropriately to fit within the overall dimensions of the device 100, and thus may have a length of about 3-7 inches (about 8-18 cm) and a diameter of about 0.25 inches to about 0.75 inches (about 0.6-2 cm).

Working Example
[0054] The air purifier was placed in a room measuring approximately 1,000 ^ft2 and tested for its ability to reduce airborne pathogens in the room. The levels of various airborne pathogens were first tested to establish baseline levels, after which the air purifier was started. The levels of the same airborne pathogens were tested again 30 and 60 minutes after the start of operation. The reduction of airborne contaminants is summarized in Table 1 below.

[0055] The data summarized above show that the air purification device was able to reduce several different types of airborne pathogens common in healthcare environments by at least a 1 or 2 log reduction, more typically by at least a 3 log reduction, or at least a 4 log reduction, and up to a 6 log reduction, in between about 30 minutes and about 60 minutes.

Additional Embodiments
[0056] The embodiments described herein may include properties, features (e.g., components, members, elements, parts, and/or portions) described in other embodiments described herein. Thus, various features of a given embodiment may be combined with and/or incorporated into other embodiments of the present disclosure. Thus, the disclosure of a particular feature with respect to a particular embodiment of the present disclosure should not be construed as limiting the application or inclusion of that feature to the particular embodiment. Rather, it will be understood that other embodiments may also include such features.

[0057]Embodiment 1: An air purification device comprising: a frame having an air inlet and an air outlet; a fan assembly configured to move air through the inlet, through an air flow passage within an interior compartment of the frame, and out the outlet; and a photocatalytic oxidation unit disposed at least partially within the air flow passage, the photocatalytic oxidation unit having a longitudinal axis that is transverse to the air flow passage, the photocatalytic oxidation unit including at least one photocatalytic cell panel extending along the longitudinal axis, one or more ultraviolet lamps extending along the longitudinal axis and configured to radiate ultraviolet light toward the at least one photocatalytic cell panel, and a reflector disposed within the photocatalytic oxidation unit.

[0058]Embodiment 2: The apparatus of embodiment 1, wherein the photocatalytic oxidation unit includes first and second ultraviolet lamps extending along a longitudinal axis and configured to radiate ultraviolet light toward at least one photocatalytic cell panel, and the reflector is an inner reflector disposed between the first and second ultraviolet lamps.

[0059]Embodiment 3: The apparatus of embodiment 2, wherein the first and second ultraviolet lamps are both oriented along a plane substantially parallel to the at least one photocatalytic cell panel.

[0060]Embodiment 4: The apparatus of embodiment 2 or embodiment 3, wherein the photocatalytic oxidation unit includes first and second photocatalytic cell panels disposed on either side of the first and second ultraviolet lamps, each extending along a longitudinal axis.

[0061]Embodiment 5: The apparatus of any one of embodiments 2 to 4, wherein the first and second ultraviolet lamps are each disposed on a plane substantially parallel to at least one photocatalytic cell panel.

[0062]Embodiment 6: The device of any one of embodiments 2 to 5, wherein the inner reflector includes a base surface and an angled feature extending obliquely from the base surface.

[0063]Embodiment 7: The device of embodiment 6, wherein the angled feature has one or more tips extending along a direction transverse to the longitudinal axis.

[0064]Embodiment 8: The device of embodiment 7, wherein one or more tips of the angled features extend along a direction substantially perpendicular to the longitudinal axis.

[0065]Embodiment 9: The apparatus of any one of embodiments 1 to 8, wherein the photocatalytic oxidation unit further includes a frame, the frame including a first outer reflector disposed outside the first ultraviolet lamp and extending inward toward the first ultraviolet lamp.

[0066]Embodiment 10: The device of embodiment 9, wherein the first outer reflector includes a tip portion that extends in a direction substantially parallel to the longitudinal axis.

[0067]Embodiment 11: The apparatus of embodiment 9 or embodiment 10, wherein the frame further includes a second outer reflector positioned outside the second ultraviolet lamp and extending inward toward the second ultraviolet lamp.

[0068]Embodiment 12: The device of embodiment 11, wherein the second outer reflector includes a tip that extends in a direction substantially parallel to the longitudinal axis.

[0069]Embodiment 13: The apparatus of any one of embodiments 1 to 12, wherein the photocatalytic oxidation unit is positioned such that the longitudinal axis is substantially perpendicular to the air flow path.

[0070]Embodiment 14: The device of any one of embodiments 1 to 13, wherein the fan assembly includes a centrifugal fan.

[0071]Embodiment 15: The apparatus of embodiment 14, wherein the axis of the centrifugal fan is substantially perpendicular to the air flow path.

[0072]Embodiment 16: The apparatus of any one of embodiments 1 to 15, wherein the fan assembly is positioned downstream of the photocatalytic oxidation unit.

[0073]Embodiment 17: The device of any one of embodiments 1 to 16, wherein the frame further includes a filter compartment configured and sized to receive a filter.

[0074]Embodiment 18: The device of embodiment 17, wherein the filter compartment is disposed between the air inlet and the photocatalytic oxidation device.

Conclusion
[0075] While certain embodiments of the present disclosure have been described in detail with reference to particular configurations, parameters, components, elements, etc., the description is illustrative and should not be construed as limiting the scope of the claimed invention.

[0076] Additionally, for any given element of a component of a described embodiment, it should be understood that any of the possible alternatives listed for that element or component may generally be used individually or in combination with each other, unless otherwise stated, implicitly or explicitly.

[0077] Also, unless otherwise noted, numerical values expressing quantities, components, distances, or other measurements used in the specification and claims are to be understood as being optionally modified by "about" or its equivalents. When the terms "about,""approximately,""substantially," and the like are used in connection with a stated quantity, value, or condition, they can be construed to mean that the quantity, value, or condition deviates by less than 20%, less than 10%, less than 5%, or less than 1% from the stated quantity, value, or condition. At the very least, and without intending to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
[0078] The headings and sub-headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the specification or the claims.

[0079] Also, note that as used in this specification and the appended claims, the singular forms "a," "an," and "the" do not exclude plural references unless the context clearly dictates. Thus, for example, an embodiment that references a singular reference term (e.g., "widget") may also include two or more such reference terms.

Claims (18)

a frame having an air inlet and an air outlet;
a fan assembly configured to move air through the air inlet , through an air flow passage within an interior compartment of the frame, and out of the air outlet ;
a photocatalytic oxidation unit disposed at least partially within the air flow path, the photocatalytic oxidation unit having a longitudinal axis that is transverse to the air flow path, the photocatalytic oxidation unit comprising:
at least one photocatalytic cell panel extending along said longitudinal axis;
one or more ultraviolet lamps extending along the longitudinal axis and configured to radiate ultraviolet light toward the at least one photocatalytic cell panel; and an inner reflector disposed within the photocatalytic oxidation unit.
A photocatalytic oxidation unit comprising:
Including ,
The photocatalytic oxidation unit includes a first ultraviolet lamp and a second ultraviolet lamp extending along the longitudinal axis and configured to radiate ultraviolet light toward the at least one photocatalytic cell panel, and the inner reflector is disposed between the first ultraviolet lamp and the second ultraviolet lamp;
The photocatalytic oxidation unit further includes a frame;
the inner reflector is formed from a folded strip of material and includes a base surface extending parallel to the longitudinal axis and an angled feature extending diagonally from the base surface and having a plate shape;
The base surface is inserted into the side wall of the frame of the photocatalytic oxidation unit;
Air purifier. 2. The apparatus of claim 1 , wherein the first ultraviolet lamp and the second ultraviolet lamp are both oriented along a plane that is substantially parallel to the at least one photocatalytic cell panel. 2. The apparatus of claim 1, wherein the photocatalytic oxidation unit includes first and second photocatalytic cell panels disposed on either side of the first and second ultraviolet lamps , each extending along the longitudinal axis. The apparatus of claim 1 , wherein the first ultraviolet lamp and the second ultraviolet lamp are each disposed on a plane substantially parallel to the at least one photocatalytic cell panel. 2. The device of claim 1, wherein the angled feature includes a first tip corresponding to a first portion of the angled feature, the first tip being a closest portion of the inner reflector to the first ultraviolet lamp, and a second tip corresponding to a second portion of the angled feature, the second tip being a closest portion of the inner reflector to the second ultraviolet lamp, both of the first tip and the second tip extending along a direction transverse to the longitudinal axis. The device of claim 5 , wherein the first tip and the second tip of the angled feature extend along a direction substantially perpendicular to the longitudinal axis. The apparatus of claim 1 , wherein the frame of the photocatalytic oxidation unit includes a first outer reflector disposed outside the first ultraviolet lamp and extending inwardly toward the first ultraviolet lamp. The apparatus of claim 7 , wherein the first outer reflector includes a tip that extends in a direction substantially parallel to the longitudinal axis. 9. The apparatus of claim 8 , wherein the frame of the photocatalytic oxidation unit further includes a second outer reflector positioned outside the second ultraviolet lamp and extending inwardly toward the second ultraviolet lamp. The apparatus of claim 9 , wherein the second outer reflector includes a tip that extends in a direction substantially parallel to the longitudinal axis. The apparatus of claim 1, wherein the photocatalytic oxidation unit is positioned such that the longitudinal axis is substantially perpendicular to the air flow path. The apparatus of claim 1, wherein the fan assembly includes a centrifugal fan. The apparatus of claim 12 , wherein the axis of the centrifugal fan is substantially perpendicular to the air flow path. The apparatus of claim 1, wherein the fan assembly is disposed downstream of the photocatalytic oxidation unit. The device of claim 1, wherein the frame further includes a filter compartment sized and shaped to receive a filter. 16. The apparatus of claim 15 , wherein the filter section is disposed between the air inlet and the photocatalytic oxidation unit . a frame having an air inlet and an air outlet;
a fan assembly configured to move air through the air inlet , through an air flow passage within an interior compartment of the frame, and out of the air outlet ;
a photocatalytic oxidation unit disposed at least partially within the air flow passage with a longitudinal axis substantially perpendicular to the air flow passage, the photocatalytic oxidation unit having a longitudinal axis that is transverse to the air flow passage, the photocatalytic oxidation unit comprising:
at least one photocatalytic cell panel extending along said longitudinal axis;
a first ultraviolet lamp and a second ultraviolet lamp extending along the longitudinal axis and configured to emit ultraviolet light toward the at least one photocatalytic cell panel;
an inner reflector disposed between the first and second ultraviolet lamps , the inner reflector being formed from a folded strip of material and including a base surface extending parallel to the longitudinal axis and an angled feature having a first portion extending obliquely from the base surface in a first direction toward the first ultraviolet lamp and a second portion extending obliquely from the base surface in an opposite second direction toward the second ultraviolet lamp;
a first outer reflector disposed outside the first ultraviolet lamp and extending inwardly toward the first ultraviolet lamp, the first outer reflector including a tip extending in a direction substantially parallel to the longitudinal axis; and
first and second photocatalytic cell panels disposed on either side of the first and second ultraviolet lamps , each extending along the longitudinal axis;
A photocatalytic oxidation unit comprising:
Including ,
The photocatalytic oxidation unit further includes a frame;
The base surface is inserted into the side wall of the frame of the photocatalytic oxidation unit;
Air purifier. The device of claim 17 , wherein the angled feature has one or more tips extending along a direction transverse to the longitudinal axis.

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